Measurement of magnetically induced electric fields in conductive media near a 60 Hz current-carrying wire

Autor: Douglas L. Miller, K. A. Robertson-De Mers
Rok vydání: 1992
Předmět:
Zdroj: Bioelectromagnetics. 13:209-221
ISSN: 1521-186X
0197-8462
DOI: 10.1002/bem.2250130305
Popis: Electric fields induced in a conductive body by the magnetic field of a current-carrying wire were analyzed theoretically and experimentally to assess the dosimetric importance of highly nonuniform, field-exposure conditions. Experimentation revealed that a 60-Hz magnetic field was inversely proportional to the radius of a wire bundle carrying 100 A within a 0.5-m2 test area. A miniaturized electric field probe was used to measure the electric fields induced in 5-cm-deep, saline-filled models. In the theoretical analysis, numerical estimates of induced fields were made by a spreadsheet method. The theoretical calculations and the measured values of induced electric fields were generally in good agreement. The induced fields were in a plane perpendicular to a vertically incident magnetic field; the maximally induced fields were in areas nearest the wire bundle. The strength of the induced field increased with model size: from 96 μV/cm in a 10 × 10 cm model to 176 μV/cm in a 40 × 40 cm model. The strength of the field induced in a 20 × 20 cm model decreased with increasing model-to-wire spacing: from 132 μV/cm for a 1-cm spacing (2-mT maximum, incident field) to 50 μV/cm for a 6-cm spacing (0.33-mT maximum). The results indicate that increases in local values of nonuniformly incident fields produce relatively small increases in induced electric fields. This finding may be important in dosimetric consideration of circumstances, such as use of electric blankets, in which fields of low average strength are accompanied by intense local fields. © 1992 Wiley-Liss, Inc.
Databáze: OpenAIRE
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